Shaft seal



Oct. 29, 1968 J. D. MCKINNEY 3,407,994

SHAFT SEAL Filed Nov. 15, 1966 3 Sheets-Sheet l Oct. 29, 1968 J. D. MCKINNEY SHAFT S EAL;

3 Sheets-Sheet 2 Filed Nov. 15, 1966 Oct. 29, 1968 J. D. MCKINNAEY SHAFT SEAL 5 Sheets-Sheet 5 Filed Nov. 15, 1966 United States Patent Olfice 3,407,994 Patented Oct. 29, 1968 SHAFT SEAL Jack D. McKinney, North Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a corporation of Delaware Filed Nov. 15, 1966, Ser. No. 594,442 4 Claims. (Cl. 230-117) ABSTRACT OF THE DISCLOSURE A seal around a shaft projecting through a wall of a fan chamber is defined by a recess formed in the back of a fan mounted on the shaft and a diverging protrusion on the fan chamber wall received in the recess. A porous gasket is positioned in the recess between the protrusion and the bottom of the recess. The eye of the fan may have a plurality of small holes through it to create a negative pressure at the rear of the fan.

The present invention relates to a seal around the shaft of an electric motor. The shaft projects through a wall and has a suction fan mounted on its end. The suction fan is adapted to be connected to a suction nozzle for picking up liquid off a floor or other surface. Thus, a wet air stream moves through the fan chamber and it is necessary to have a good seal around the motor shaft in order to prevent moisture from entering the motor chamber where it could do great damage. Prior efforts to effect a reliable seal in this environment have not been completely satisfactory either because they are subject to some leakage or wear out rapidly.

In accordance with the present invention a motor is horizontally mounted with its shaft projecting through a barrier wall into a suction fan chamber. A centrifugal type suction fan is mounted on the shaft in the fan chamber and a protrusion extends outward around the shaft from the barrier wall toward the fan. The protrusion diverges outwardly from the barrier wall so that moisture collecting on the barrier wall flows down around the protrusion and is kept from the shaft by the diverging shape. The back of the fan has a circular recess therein and receives an end portion of the protrusion. The fan has a plurality of holes formed therethrough at its eye and the holes open into the recess in the fan back. The holes provide airflow from the back toward the front of the fan and any moisture which does get between'the protrusion and the fan is pulled through the holes away from the shaft. A porous gasket is positioned around the shaft between the protrusion and the bottom wall of the recess as an added precaution. The fan chamber includes an annular wall surrounding the periphery of the fan and a plurality of elongated ribs project inwardly from the annular wall to keep moisture from the back of the fan.

Therefore, it is an object of this invention to provide a seal around a shaft where the shaft projects through a wall into a fan chamber by forming holes through the fan at its eye to cause airflow from the back to the front of the fan.

It is another object of this invention to provide such a seal by providing a protrusion on the wall through which the shaft projects and forming the protrusion with a diverging outer surface.

It is a further object of this invention to provide ribs on the annular wall of the fan chamber to keep liquid from behind the fan.

Other objects and advantages will be apparent to those skilled in the art when taken in connection with the accompanying drawing wherein:

FIGURE 1 is an end view in partial section showing a fan chamber having the shaft seal of the present invention embodied therein.

FIGURE 2 is a top sectional view taken on line 22 of FIG. 1.

FIGURE 3 is a top view taken on line 2--2 of FIG. 1 with parts omitted to show the interior of the fan chamber.

FIGURE 4 is a partial sectional view taken on line 4--4 of FIG. 1.

FIGURE 5 is an exploded isometric view showing the shaft seal of the present invention.

Referring now to the drawing, FIG. 1 shows a motor casing and fan chamber having top half 1 and bottom half 2. Halves 1 and 2 are complementary to one another and are joined together along line 3 as by screws extending through holes in the edges of the top half and into bored bosses as at 4, 5, 6 and 7 on bottom half 2 in FIG. 2. Arcuate opening 8 in top half 1 and arcuate opening 9 in bottom half 2 cooperate to form an inlet into a fan chamber housing centrifugal fan 10. Arcuate recesses 11 and 12 in top half 1 and bottom half 2 are formed in the peripheral wall of the fan chamber cooperate to define an outlet.

As shown in FIG. 2 bottom casing half 2 has supports 13 and 14 rotatably supporting shaft 15 of motor 16 in bearings 17 and 18 in a well known manner. Casing halves 1 and 2 include barrier wall forming portions 19 and 20 each having an arcuate opening 21 and 22 which cooperate when halves 1 and 2 are secured together to form a circular opening which receives protrusion member 23. Arcuate openings 21 and 22 are recessed as at 24 and 25 and gaskets 26 and 27 are received in the recesses. Recesses 21 and 22 sealingly receive the peripheral portion of protrusion member 23. Protrusion member 23 has a control opening 28 therein through which shaft 15 extends. Taken together, walls 19 and 20, and protrusion member 23 define a barrier wall separating motor 16 from the fan chamber. Shaft 15 projects through opening 28 to define a projecting shaft end on which fan 10 is mounted and secured as by nut 29 threaded onto the end of shaft 15. Fan 10 has an elongated bored hub 30 having flattened portion 31 which drivingly keys with flattened portion 32 on shaft 15. As shown in FIGS. 2 and 4, hub 30 extends through opening 28 in protrusion member 23 and a motor ventilating fan 33 is adhesively secured to hub 30 and discharges motor cooling air out as at 34 in FIG. 2.

Protrusion member 23 has protrusion 35 thereon which surrounds hub 30 and diverges outwardly from member 23 toward fan 10 in a substantially frusto-conical shape. It will be understood that elongated hub 30 could be omitted by securing fans 10 and 33 individually on shaft 15 so that protrusion 35 directly surrounds shaft 15. In the manner shown hub 30 actually defines part of shaft 15. Fan 10 has a circular recess 36 formed in its back to receive the end portion of protrusion 35. A porous gasket 37 of felt material or the like is positioned around hub 30 between the forward face of protrusion 35 and the bottom wall of recess 36. The forward face of protrusion 35 is recessed at 38 to receive a portion of gasket 37.

Fan 10 has its eye axially of shaft 15 and in alignment with the opening formed by arcuate openings 8 and 9. The eye defines an area of low pressure and a plurality of holes as at 39 and 40 in FIG. 2, and at 41 and 42 in FIG. 4 are formed through fan 10 at its eye. Holes 39, 40, 41 and 42 enter recess 36 in the back and fan 10 slightly outward of the sidewall of recess 36 and below the edge of protrusion 35. The holes also enter recess 36 adjacent gasket 37 and the holes are open outwardly of the gasket. Casings 1 and 2 include annular walls 43 and 44 surrounding fan 10 to define the periph- 3 eral wall of the fan casing. Walls 43 and 44 have ribs 45, 46, 47, 48, 49 and 50 which define channels therebetween. When moist air enters the fan chamber the blades of fan throw moisture against the interior surfaces of'walls 43 and 44. This moisture could flow or be thrown behind fan 10 where it might get to the seal. The ribs keep the moisture on the interior surfaces of walls 43 and 44 until it is discharged through the outlet formed by recessed openings 11 and 12. The ribs help considerably to keep moisture from behind fan 10. One rib as 48 and 45 should be closely adjacent the back of fan 10 so that moisture cannot be thrown between rib 48 and wall or rib 45 and wall 19.

In operation the inlet to the fan chamber formed by recessed arcuate openings 8 and 9 is connected to a suc tion nozzle for picking up liquid from a floor or other surface. The moist air enters the fan chamber and is discharged through the outlet formed by arcuate recessed openings 11 and 12. The moist air is whipped around in the fan chamber by fan 10 and ribs 45-50 on the peripheral wall of the fan chamber help to keep moisture from behind fan 10. Some moisture does get behind fan 10 where it is blown around and also collects on the back of the fan and the barrier wall formed by walls 19 and 20, and protrusion member 23. Moisture flowing down wall 19 and the back of fan 10 when the fan is turned off heads toward hub and shaft 15. Moisture flowing down the surfaces and being blown around when the fan is operating also flows toward hub 30 and shaft 15. The diverging outer surface of protrusion 35, at least at its top portion, keep moisture away from opening 28 in member 23. Any liquid dripping off the other end of protrusion may fall in recess 36 in the back of fan 10 but it falls or is thrown out, or is pulled back to the front of fan 10 and away from opening 28 through holes 39-42. Holes 39-42 cause a flow of air from the back to the front of the fan and continuously pull moisture away from opening 28 so that it cannot enter the motor casing. Porous gasket 37 traps any large amounts of moisture and the gasket is dried by the air flowing through holes 39-42. Holes 39-42 tend to induce airflow through opening 28 around hub 30 and this helps keep moisture out of the motor casing.

Those skilled in the art will readily appreciate the novel and advantageous features provided by the shaft seal of the present invention. While only one embodiment of the present invention has been shown and described it is to be understood that it is only illustrative and 4 is not to be taken in a limiting sense. The present invention includes all equivalent variations of the embodiment disclosed and is limited only by the scope of the claims.

I claim:

1. In a motor mounted in a casing and having a shaft projecting through a barrier wall of said casing to define a projecting shaft end,

(a) a suction fan mounted on said projecting shaft end, said fan having an intake eye portion defining an area of low pressure, t

(b) a protrusion on said barrier wall projecting outwardly around said shaft toward said fan,

(c) a circular recess in the back of said fan around said shaft, said recess having a bottom wall,

(d) said protrusion having its outer end received in said recess,

(e) a plurality of holes through said eye portion of said fan, said holes extending from said recess to the front of said fan, and

(f) a porous gasket positioned around said shaft between said protrusion and the bottom wall of said recess.

2. The device of claim 1 wherein said fan has an elongated hub extending through said barrier wall, said protrusion and said gasket surrounding said hub.

3. The device of claim 1 wherein said protrusion has at least its upper outer surface diverging outwardly from said barrier wall toward said fan, said protrusion including an outer end portion having an annular recess therein, at least a portion of said gasket received in said recess, and said holes having at least a portion thereof radially outward of said gasket.

4. The device of claim 3 and further including a fan chamber surrounding said fan, said chamber having an annular wall, the inner surface of said annular wall having continuous ribs thereon projecting inwardly toward said fan.

References Cited UNITED STATES PATENTS 1,261,806 4/ 1918 Greenawalt. 1,756,324 4/ 1930 Wilfley. 2,612,844 10/1952 Grise 103-11l XR 2,649,050 8/1953 Dibdin 103-103 2,671,406 3/1954 Waller 103103 ROBERT M. WALKER, Primary Examiner. 

